Right heart morphology and function in heart transplantation recipients

A Comprehensive Excursus of the Roles of Echocardiography in Heart Transplantation Follow-Up

Current guidelines for the care of heart transplantation recipients recommend routine endomyocardial biopsy and invasive coronary angiography as the cornerstones in the surveillance for acute rejection (AR) and coronary allograft vasculopathy (CAV). Non-invasive tools, including coronary computed tomography angiography and cardiac magnetic resonance, have been introduced into guidelines without roles of their own as gold standards. These techniques also carry the risk of contrast-related kidney injury. There is a need to explore non-invasive approaches providing valuable information while minimizing risks and allowing their application independently of patient comorbidities. Echocardiographic examination can be performed at bedside, serially repeated, and does not carry the burden of contrast-related kidney injury and procedure-related risk. It provides comprehensive assessment of cardiac morphology and function. Advanced echocardiography techniques, including Doppler tissue imaging and strain imaging, may be sensitive tools for the detection of minor myocardial dysfunction, thus providing insight into early detection of AR and CAV. Stress echocardiography may offer a valuable tool in the detection of CAV, while the assessment of coronary flow reserve can unravel coronary microvascular impairment and add prognostic value to conventional stress echocardiography. The review highlights the role of Doppler echocardiography in heart transplantation follow-up, weighting advantages and limitations of the different techniques.

Right Ventricular Function on Cardiovascular Magnetic Resonance Imaging and Long-Term Outcomes in Stable Heart Transplant Recipients

BACKGROUND

In heart transplant recipients, right ventricular (RV) dysfunction may occur for a variety of reasons. Whether RV dysfunction in the stable phase after heart transplantation is associated with long-term adverse outcomes is unknown. We aimed to determine the long-term prognostic significance of RV dysfunction identified on cardiovascular magnetic resonance imaging (CMR) at least 1 year after heart transplantation.

METHODS

In consecutive heart transplant recipients who underwent CMR for surveillance, we assessed 2 CMR measures of RV function: RV ejection fraction and RV global longitudinal strain (RVGLS). We investigated associations between RV dysfunction and a composite end point of death or major adverse cardiac events, including retransplantation, nonfatal myocardial infarction, coronary revascularization, and heart failure hospitalization.

RESULTS

A total of 257 heart transplant recipients (median age, 59 years; 75% men) who had CMR at a median of 4.3 years after heart transplantation were included. Over a median follow-up of 4.4 years after the CMR, 108 recipients experienced death or major adverse cardiac events. In a multivariable Cox regression analysis adjusted for age, time since transplantation, indication for transplantation, cardiac allograft vasculopathy, history of rejection, and CMR covariates, RV ejection fraction was not associated with the composite end point, but RVGLS was independently associated with the composite end point with a hazard ratio of 1.08 per 1% worsening in RVGLS ([95% CI, 1.00-1.17]; P=0.046). RVGLS provided incremental prognostic value over other variables in multivariable analyses. The association was replicated in subgroups of recipients with normal RV ejection fraction and recipients with late gadolinium enhancement imaging. A similar association was seen with a composite end point of cardiovascular death or major adverse cardiac events.

CONCLUSIONS

CMR feature tracking-derived RVGLS assessed at least 1 year after heart transplantation was independently associated with the long-term risk of death or major adverse cardiac events. Future studies should investigate its role in guiding clinical decision-making in heart transplant recipients.

Echocardiographic assessment of pediatric heart transplantation: A single-center experience in China

BACKGROUND

Pediatric heart transplant (HT) has become the standard of care for end-stage heart failure in children worldwide. Serial echocardiographic evaluations of graft anatomy and function during follow-up are crucial for post-HT management. However, evolution of cardiac structure and function after pediatric HT has not been well described, especially during first year post-HT. This study aimed to characterize the evolution of cardiac structure and function after pediatric HT and investigate the correlation between biventricular function with adverse clinical outcomes.

METHODS

A single-center retrospective study of echocardiographic data obtained among 99 pediatric HT patients was conducted. Comprehensive echocardiographic examination was performed in all patients at 1-, 3-, 6-, 9- and 12-months post-HT. We obtained structural, functional and hemodynamic parameters from both left- and right-side heart, such as left ventricular stroke volume (LVSV), left ventricular ejection fraction (LVEF), right ventricular fractional area change (RVFAC), etc. The cardiac evolution of pediatric HT patients during first post-HT year was described and compared between different time points. We also explored the correlation between cardiac function and major adverse transplant events (MATEs).

RESULTS

1) Evolution of left heart parameters: left atrial length, mitral E velocity, E/A ratio, LVSV and LVEF significantly increased while mitral A velocity significantly decreased over the first year after HT (P < .05). Compared with 1 month after HT, interventricular septum (IVS) and left ventricular posterior wall (LVPW) decreased at 3 months but increased afterwards. (2) Evolution of right heart parameters: right ventricular base diameter and mid-diameter; right ventricular length diameter, tricuspid E velocity, E/A ratio, tricuspid annular velocity e' at free wall, and RVFAC increased, while tricuspid A velocity decreased over the first year after HT (P < .05). (3) Univariate logistic regression model suggests that biventricular function parameters at 1-year post-HT (LVEF, RVFAC, tricuspid annular plane systolic excursion and tricuspid lateral annular systolic velocity) were associated with MATEs.

CONCLUSION

Gradual improvement of LV and RV function was seen in pediatric HT patients within the first year. Biventricular function parameters associated with MATEs. The results of this study pave way for designing larger and longer follow-up of this population, potentially aiming at using multiparameter echocardiographic prediction of adverse events.

Tricuspid Annular Plane Systolic Excursion (TAPSE) correlates with mean pulmonary artery pressure especially 10 years after pediatric heart transplantation

Tricuspid annular plane systolic excursion (TAPSE) is important in the noninvasive echocardiographic assessment of right heart function. This retrospective observational study shows correlations of TAPSE with invasive right heart catheterization parameters after pediatric heart transplantation (HTx). The study included patients after pediatric HTx with cardiac catheterizations in 2018/2019 and measurement of TAPSE (n = 52 patients with 57 examinations; 50.9% adults, 52.6% female, median age: 18.54 years). TAPSE was compared with normal values. Stepwise, linear and multiple regression were used to show influencing variables on TAPSE. Mean TAPSE z-score was -3.48 (SD: 2.25) and 68.4% of HTx-recipients showed abnormally reduced TAPSE (z-score ←2) compared to normal values. Multiple regression (p-value <0.001; corrected R² = 0.338) showed significant correlations of time since HTx (p-value <0.001) and mPAP (p-value: 0.008) with TAPSE z-scores. Divided into subgroups (time since HTx <10 and ≥10 years), TAPSE and mPAP correlated only ≥10 years after HTx (p-value = 0.002). This study provides data of TAPSE even ≥10 years after pediatric HTx. Most patients showed a decreased TAPSE early after HTx, which improved over time. TAPSE z-scores correlated significantly with time since HTx and mPAP, especially ≥10 years post-HTx. Therefore, TAPSE must be used carefully in the early follow-up.

Serial changes of right ventricular function assessed by three-dimensional speckle-tracking echocardiography in clinically well adult heart transplantation patients

PURPOSE

The present study aimed to evaluate serial changes of right ventricular (RV) function in clinically well adult heart transplantation (HT) patients using three-dimensional speckle-tracking echocardiography (3D-STE).

METHODS

We included 58 adult HT patients, who were free from severe valvular insufficiency, severe coronary artery disease, acute rejection, or multiple organ transplantation, and 58 healthy controls. The healthy controls were matched by the distribution of age and sex with HT group. Conventional and three-dimensional (3D) echocardiography was performed in all HT patients at 1-, 3-, 6-, 9- and 12-months post-HT. And all the healthy controls underwent conventional and 3D echocardiography when recruited. Tricuspid annular plane systolic excursion (TAPSE), S' and RV fractional area change (RV FAC) were measured. Two-dimensional RV free wall longitudinal strain (2D-RV FWLS) was derived from two-dimensional speckle-tracking echocardiography (2D-STE). 3D RV free wall longitudinal strain (3D-RV FWLS) and RV ejection fraction (RVEF) were assessed by 3D-STE.

RESULTS

TAPSE, S', RV FAC, 2D-RV FWLS, 3D-RV FWLS, and RVEF increased significantly from 1 to 6 months post-HT (P < 0.05). TAPSE, S', RV FAC and 2D-RV FWLS showed no significant changes from 6 to 12 months post-HT (P > 0.05), while 3D-RV FWLS and RVEF were still significantly increased: 3D-RV FWLS (17.9 ± 1.0% vs. 18.7 ± 1.4%, P < 0.001) and RVEF (45.9 ± 2.2% vs. 46.8 ± 2.0%, P = 0.025). By 12 months post-HT, TAPSE, S', RV FAC, 2D-RV FWLS, 3D-RV FWLS and RVEF were significantly lower than the healthy controls: TAPSE (15.1 ± 2.1 mm vs. 23.5 ± 3.0 mm, P < 0.001), s' (10.3 ± 1.9 cm/s vs. 12.9 ± 2.0 cm/s, P < 0.001), RV FAC (45.3 ± 1.8% vs. 49.2 ± 3.8%, P < 0.001), 2D-RV FWLS (19.9 ± 2.3% vs. 23.5 ± 3.8%, P < 0.001), 3D-RV FWLS (18.7 ± 1.4% vs. 22.4 ± 2.3%, P < 0.001) and RVEF (46.8 ± 2.0% vs. 49.9 ± 5.7%, P < 0.001).

CONCLUSION

RV systolic function improved significantly over time in clinically well adult HT patients even up to 12 months post-HT. By 12 months post-HT, the patient's RV systolic function remained lower than the control. 3D-STE may be more suitable to assess RV systolic function in HT patients.

Prognostic value of feature-tracking right ventricular longitudinal strain in heart transplant recipients

OBJECTIVES

The prognostic value of cardiac magnetic resonance feature tracking (CMR-FT)-derived right ventricular longitudinal strain (RVLS) post-heart transplantation has not been studied. This study aimed to evaluate the prognostic significance of CMR-FT-derived RVLS, in patients post- heart transplantation and to directly compare its value with that of conventional RV ejection fraction (RVEF).

METHODS

In a cohort of consecutive heart transplantation recipients who underwent CMR for surveillance, RVLS from the free wall was measured by CMR-FT. The composite endpoint was all-cause death or major adverse cardiac events. The Cox regression model was used to examine the independent association between RVLS and the endpoint.

RESULTS

A total of 96 heart transplantation recipients were retrospectively included. Over a median follow-up of 41 months, 20 recipients reached the composite endpoint. The multivariate Cox analysis showed that the model with RVLS (hazard ratio [HR]:1.334; 95% confidence interval [CI]:1.148 to 1.549; p < 0.001; Akaike information criterion [AIC] = 140, C-index = 0.831) was better in predicting adverse events than the model with RVEF (HR:0.928; 95% CI: 0.868 to 0.993; p = 0.030; AIC = 149, C-index = 0.751). Furthermore, receiver operating characteristic curves revealed that the accuracy for predicting adverse events was greater for RVLS than RVEF (area under the curve: 0.85 vs 0.76, p = 0.03).

CONCLUSIONS

CMR-FT-derived RVLS is an independent predictor of adverse events in post-heart transplantation, and its predictive value was better than RVEF. Therefore, our study highlighted the importance of evaluating RVLS for risk stratification after heart transplantation.

KEY POINTS

• CMR-RVLS is an independent predictor of adverse events post-heart transplantation and provides greater predictive value. • CMR-RVLS may help clinicians to risk stratification in heart transplantation recipients.

Evaluation of the myocardial deformation in the diagnosis of rejection after heart transplantation

Introduction

Heart transplantation represents main therapy for end-stage heart failure. However, survival after transplantation is limited by development of graft rejection. Endomyocardial biopsy, an invasive and expensive procedure, is gold standard technique for diagnosis of rejection. Most of biopsy complications are observed using echocardiography. Novel echocardiographic techniques, such as myocardial strain and three-dimensional reconstruction, can be useful in heart transplant patients.

Purpose

To evaluate ventricular strain in heart transplant patients and association with rejection, cellular or humoral, as well as two- and three-dimensional echocardiographic parameters.

Methods

Cohort of patients from heart transplant program taken to echocardiography after endomyocardial biopsy, from December 2017 to January 2020. Ventricular strain and three-dimensional left ventricle parameters were studied. Rejection results were retrieved from medical record. Qualitative variables were expressed by absolute frequency and percentages, while continuous variables by means and standard deviations. Association between rejection and variables of interest was measured by odds ratio and confidence interval of 95%, with p-value < 0.05.

Results

123 post-endomyocardial biopsy echocardiographic exams were performed in 54 patients. Eighteen exams were excluded, lasting 105 exams to be evaluated for conventional and advanced echocardiographic parameters. Male patients were 60.4%. Prevalence of cellular rejection was 8.6%, humoral rejection 12.4%, and rejection of any type 20%. There was no association between right ventricular strain and rejection, whether cellular (p = 0.118 and p = 0.227 for septum and free wall, respectively), humoral (p = 0.845 and p = 0.283, respectively), or of any type (0.504 and 0.446). There was no correlation between rejection and left ventricle global longitudinal strain, three-dimensional ejection fraction or desynchrony index. Conventional parameters associated to rejection were left ventricle posterior wall thickness [OR 1.660 (1.163; 2.370), p = 0.005] and left ventricle mass index [OR 1.027 (1.011; 1.139), p = 0.001]. Left ventricle posterior wall thickness remained significant after analysis of cellular and humoral rejection separately [OR 1.825 (1.097; 3.036), p = 0.021 and OR 1.650 (1.028; 2.648), p = 0.038, respectively].

Conclusions

There was no association between ventricular strain, three-dimensional left ventricular ejection fraction and the desynchrony index and rejection, cellular or humoral. Evidence of association of graft rejection with left ventricle posterior wall thickness and left ventricle mass index was observed.

Residual Pulmonary Vascular Resistance Increase Under Left Ventricular Assist Device Support Predicts Long-Term Cardiac Function After Heart Transplantation

Aims

We compared hemodynamics and clinical events after heart transplantation (HTx) in patients stratified by the severity of residual pulmonary vascular resistance (PVR) after left ventricular assist device (LVAD) implantation for bridge to transplantation.

Methods

We retrospectively analyzed patients who had undergone HTx at the University of Tokyo Hospital. We defined the high PVR group as patients with PVR of >3 Wood Units (WU) as measured by right heart catheterization performed 1 month after LVAD implantation.

Results

We included 85 consecutive HTx recipients, 20 of whom were classified in the high PVR group and 65 in the low PVR group. The difference in PVR between the two groups became apparent at 2 years after HTx (the high PVR group: 1.77 ± 0.41 WU, the low PVR group: 1.24 ± 0.59 WU, p = 0.0009). The differences in mean pulmonary artery pressure (mPAP), mean right arterial pressure (mRAP), and mean pulmonary capillary wedge pressure (mPCWP) tended to increase from the first year after HTx, and were all significantly higher in the high PVR group at 3 years after HTx (mPAP: 22.7 ± 9.0 mm Hg vs. 15.4 ± 4.3 mm Hg, p = 0.0009, mRAP: 7.2 ± 3.6 mm Hg vs. 4.1 ± 2.1 mm Hg, p = 0.0042, and mPCWP: 13.4 ± 4.5 mm Hg, 8.8 ± 3.3 mm Hg, p = 0.0040). In addition, pulmonary artery pulsatility index was significantly lower in the high PVR group than in the low PVR group at 3 years after HTx (2.51 ± 1.00 vs. 5.21 ± 3.23, p = 0.0033). The composite event including hospitalization for heart failure, diuretic use, and elevated intracardiac pressure (mRAP ≥ 12 mm Hg or mPCWP ≥ 18 mm Hg) between the two groups was significantly more common in the high PVR group. Residual high PVR was still an important predictor (hazard ratio 6.5, 95% confidence interval 2.0–21.6, and p = 0.0023) after multivariate Cox regression analysis.

Conclusion

Our study demonstrates that patients with residual high PVR under LVAD implantation showed the increase of right and left atrial pressure in the chronic phase after HTx.

Reference Values of Right Ventricular Volumes and Ejection Fraction by Three-Dimensional Echocardiography in Adults: A Systematic Review and Meta-Analysis

Objective: This study was conducted in order to determine the reference values for right ventricular (RV) volumes and ejection fraction (EF) using three-dimensional echocardiography (3DE) and to identify sources of variance through a systematic review and meta-analysis.

Methods: This systematic review was preregistered with the International Prospective Register of Systematic Reviews (https://www.crd.york.ac.uk/PROSPERO/) (CRD42020211002). Relevant studies were identified by searches of the PubMed, Embase, and Cochrane Library databases through October 12, 2020. Pooled reference values were calculated using the random-effects model weighted by inverse variance. Meta-regression analysis and Egger's test were used to determine the source of heterogeneity. A subgroup analysis was performed to evaluate the reference values across different conditions.

Results: The search identified 25 studies of 2,165 subjects. The mean reference values were as follows: RV end-diastolic volume, 100.71 ml [95% confidence interval (CI), 90.92–110.51 ml); RV end-systolic volume, 44.19 ml (95% CI, 39.05–49.33 ml); RV end-diastolic volume indexed, 57.01 ml/m² (95% CI, 51.93–62.08 ml/m²); RV end-systolic volume indexed, 25.41 ml/m² (95% CI, 22.58–28.24 ml/m²); and RVEF, 56.20% (95% CI, 54.59–57.82%). The sex- and age-specific reference values were assessed according to the studies reporting the values of different sexes and age distributions, respectively. In addition, the vendor- and software-specific reference values were analyzed. The meta-regression analysis revealed that sex, frame rate, pulmonary artery systolic pressure, and software packages were associated with variations in RV volumes (P < 0.05). Inter-vendor and inter-software discrepancies may explain the variability of RVEF.

Conclusions: The reference values for RV volumes and RVEF using 3DE were assessed. The confounders that impacted the variability in RV volumes or RVEF contained the sex, frame rate, pulmonary artery systolic pressure, inter-vendor discrepancies, and inter-software discrepancies.

Echocardiographic assessment of chamber size and ventricular function during the first year after heart transplantation

AIMS

Detecting changes in ventricular function after orthotopic heart transplantation (OHT) using transthoracic echocardiography (TTE) is important but interpretation of findings is complicated by lack of data on early graft adaptation. We sought to evaluate echocardiographic measures of ventricular size and function the first year following OHT including speckle tracking derived strain. We also aimed to compare echocardiographic findings to haemodynamic parameters obtained by right heart catheterization (RHC).

METHODS AND RESULTS

Fifty OHT patients were examined prospectively with TTE and RHC at 1, 6, and 12 months after OHT. Left ventricle (LV) was assessed with fractional shortening, ejection fraction and systolic tissue velocities. Right ventricular (RV) evaluation included tricuspid annular plane systolic excursion (TAPSE), systolic tissue velocity (S´) and fractional area change (FAC). LV global longitudinal and circumferential strain and RV global longitudinal strain (GLS) and RV lateral wall strain (RVfree) were analysed. No relevant changes occurred in LV echocardiographic parameters, whereas all measures of RV function improved significantly during follow-up. There was an increase in TAPSE (12.4 ± 3.3 mm to 14.4 ± 4.3 mm, p < .01), FAC (36% ± 8% to 41% ± 8%, p < .01), RV GLS (-15.8% ± 4% to -17.8% ± 3.6%, p < .01), and RVfree (-15.5% ± 3.7% to -18.6% ± 3.6%, p < .001). Between 1 and 12 months, pulmonary pressures decreased, whereas pulmonary vascular resistance did not.

CONCLUSION

Stable OHT recipients reached steady state regarding LV function 1 month after transplantation. In contrast, RV function displayed gradual improvement the first year following OHT, indicating delayed RV adaptation as compared to the LV. Improved RV function parameters were independent of invasively measured pulmonary pressures.

Assessment of biventricular function by three-dimensional speckle-tracking echocardiography in clinically well pediatric heart transplantation patients

BACKGROUND

The biventricular function plays an important role in the prognosis of pediatric heart transplantation (HTx) patients. Therefore, in this study, we aimed to evaluate the biventricular function of pediatric HTx patients by three-dimensional (3D) speckle-tracking echocardiography (3D-STE).

METHODS

We enrolled 30 clinically well pediatric HTx patients and 30 healthy controls with a similar distribution of sex and age to the HTx. All participants underwent comprehensive two-dimensional (2D) and 3D echocardiography. Left ventricular (LV) global longitudinal strain (GLS), global circumferential strain (GCS), left and right ventricular ejection fraction (LVEF and RVEF, respectively), and right ventricular free wall longitudinal strain (RV FWLS) were acquired by 3D-STE. Moreover, the correlations between strains and clinical data were explored.

RESULTS

Compared with controls, LV GLS was decreased in pediatric HTx patients (P < .05), while LV GCS and LVEF showed no difference. LV GLS showed a weak correlation with cold ischemic time in HTx group (r = 0.396, P < .05). Meanwhile, RVEF and RV FWLS were significantly lower in the HTx group (P < .05). In the HTx group, RV FWLS showed a weak correlation with the preoperative mean pulmonary artery pressure (r = 0.420, P < .05) and postoperative pulmonary artery systolic pressure (r = 0.465, P < .05).

CONCLUSION

The 3D-biventricular mechanical functions were decreased in clinically well pediatric HTx patients. The provided characteristics and appropriate normal values of biventricular mechanical functions can be the basis in subsequent studies in the pediatric HTx patients.

Heart transplantation ten-year follow-ups: Deformation differentiation comparison of myocardial performance in left ventricle and right ventricle

BACKGROUND

We try to investigate whether the values of three-dimensional principal longitudinal strain present differently between the left and right ventricles in patients with long-time follow-ups after heart transplantation (HTx).

METHODS AND RESULTS

Transthoracic echocardiography with three-dimensional speckle tracking was performed at one-, five- and ten-year follow-ups in 62 "healthy" HTx patients together with routine echocardiographic evaluation in 32 control group (CG) individuals. Longitudinal strain was applied in all subjects assessing without myocardium wall motion abnormality. Firstly, left ventricular ejection fraction preserved in HTx and had no significant difference in comparison with the controls (p > .05). 3D measurement showed obvious reduction in global (%: CG: -20.5 ± 3.5 vs. HT1y: -13.7 ± 4.6, HT5y: -14.4 ± 4.5, HT10y: -14.6 ± 4.7. p < .01) and horizontal segmental (basal, mid, apical, CG vs. HTx: all p < .01) strain values of the left compared HTx with control subjects. Secondly, tissue Doppler imaging s' velocity and tricuspid annular plane systolic excursion reduced in HTx as compared to the controls in right ventricle (p < .01). Longitudinal strain presented a more distinctive reduction in global (%: CG: -24.5 ± 4.6 vs. HT1y:-14.8 ± 7.5, HT5y: -15.5 ± 6.4, HT10y: -15.9 ± 6.8. p < .01) and horizontal segmental (basal, mid, apical, CG vs. HTx: all p < .01) average values of the right compared HTx with control subjects. Thirdly, there weren't any significant changes between one-, five- and ten-year of all the values with HTx inter-group comparison in both the left and right ventricles (p > .05). Fourthly, the global and segmental strain of the right ventricle decreased more than that of the left ventricle in all HTx groups, with the global decreased differentiation rates of 7%, 7%, 6%, respectively.

CONCLUSIONS

Compared HTx with control subjects in both ventricles, conventional evaluation showed preserved or decreased functions in the left and right separately. Myocardial function evaluating by 3D longitudinal strain reduced after HTx, but the deformation of the right ventricle reduced more than those of the left ventricle. Additionally, 3D strain values almost remained with stable decreased differentiation rates during the long-time follow-ups.

Cardiac Magnetic Resonance Feature Tracking Global Longitudinal Strain and Prognosis After Heart Transplantation

OBJECTIVES

This study determined the long-term prognostic significance of GLS assessed using CMR-FT in a large cohort of heart transplant recipients.

BACKGROUND

In heart transplant recipients, global longitudinal strain (GLS) assessed using echocardiography has shown promise in the prediction of clinical outcomes. We hypothesized that CMR feature tracking (CMR-FT) GLS is independently associated with long-term outcomes in heart transplant recipients.

METHODS

In a cohort of consecutive heart transplant recipients who underwent routine CMR for clinical surveillance, CMR-FT GLS was calculated from 3 long-axis cine CMR images. Associations between GLS and a composite endpoint of death or major adverse cardiac events (MACE), including retransplantation, nonfatal myocardial infarction, coronary revascularization, and heart failure hospitalization, were investigated.

RESULTS

A total of 152 heart transplant recipients (age 54 ± 15 years; 29% women; 5.0 ± 5.4 years after heart transplantation) were included. The median GLS was -11.6% (interquartile range: -13.6% to -9.2%). Over a median follow-up of 2.6 years, 59 recipients reached the composite endpoint. On Kaplan-Meier analyses, recipients with GLS worse than the median had a higher estimated cumulative incidence of the composite endpoint compared with recipients with GLS better than the median (log rank p = 0.004). On multivariate Cox proportional hazards regression, GLS was independently associated with the composite endpoint after adjustment for cardiac allograft vasculopathy, history of rejection, left ventricular ejection fraction (LVEF), right ventricular EF, and presence of myocardial fibrosis, with a hazard ratio of 1.15 for every 1% worsening in GLS (95% confidence interval: 1.06 to 1.24; p < 0.001). Similar results were seen in subgroups of recipients with LVEF >50% and with no myocardial fibrosis. GLS provided incremental prognostic value over other variables in the multivariate model as determined by the log-likelihood chi-squared test.

CONCLUSIONS

In a large cohort of heart transplant recipients, CMR-FT GLS was independently associated with the long-term risk of death or MACE.

Impact of right ventricular systolic function after heart transplantation on exercise capacity

BACKGROUND

Right ventricular (RV) systolic parameters are difficult to assess in heart transplant recipients (HTRs) compared to healthy people because of discordant data, and their impact on exercise capacity remains undefined. We sought to retrospectively assess the impact of RV systolic function on exercise capacity after heart transplantation.

METHODS

We analyzed data from 61 HTRs who underwent transthoracic echocardiography (TTE), cardiac magnetic resonance imaging (CMR), and exercise capacity assessment by 6-minute walking test (6MWT) and cardiopulmonary exercise testing (CPET) at 1- and 2-year follow-ups.

RESULTS

Transthoracic echocardiography RV longitudinal systolic function including tricuspid annular plan systolic excursion (TAPSE), peak systolic S' wave tricuspid annular velocity (PSVtdi) and RV free wall longitudinal strain was decreased at 1 year (respectively, 15 ± 3 mm, 10 ± 3 cm/s, and -19 ± 5%) and at 2 years (respectively, 15 ± 3 mm, 10 ± 2 cm/s, and -20 ± 5%) with no significant difference between both evaluations; meanwhile, RV ejection fraction (RVEF) measured by CMR was preserved. Mean percentage of predicted peak oxygen consumption was altered, but improved between the first and second year (55 ± 18 vs 60 ± 18%, P = .038). PSVtdi was weakly correlated with 6MWT distance (r = .426, P = .017) and RVEF with the predicted distance at 6MWT (r = .410, P = .027) at the 1-year follow-up.

CONCLUSIONS

Despite decreasing values, RV longitudinal systolic function has a weak impact on exercise capacity of HTRs. PSVtdi and RVEF are the most pertinent parameters to assess the impact of RV systolic function on exercise capacity after heart transplantation. These results should lead to redefine normal RV systolic function thresholds for HTRs.

Left and right ventricular function detection and myocardial deformation analysis in heart transplant patients with long-time follow-ups

OBJECTIVE

We try to investigate whether the values of longitudinal strain present differences between the left and right ventricles in long-time follow-ups after heart transplantation (HTx) with dynamic changes in function.

METHODS AND RESULTS

Follow-up transthoracic echocardiography was performed in 1- and 3-month and 1- and 5-year follow-ups in 50 "healthy" HTx patients and compared with 26 control subjects. The left ventricle with preserved ejection fraction evaluated by biplane Simpson (control group [CG] vs HT; P > .05) had an obvious reduction in global (CG: -20.49 ± 2.38 vs heart transplant 1 month [HT1m]: -13.06 ± 2.86, heart transplant 3 month [HT3m]: -13.61 ± 2.61, heart transplant 1 year [HT1y]: -13.69 ± 4.56, heart transplant 5 year [HT5y]: -14.41 ± 4.54; P < .001) and horizontal segmental (basal, mid, apical) (P < .001) together with chamber segmental (apical 4-chamber, apical 3-chamber, apical 2-chamber) (P < .001) average strain values. The right ventricle with reduced ventricular function measured by tissue Doppler imaging S' and tricuspid annular plane systolic excursion had a more distinctive reduction in global (CG: -24.53 ± 4.20 vs HT1m: -12.94 ± 5.03, HT3m: -13.68 ± 4.35, HT1y: -14.95 ± 7.50, HT5y: -15.20 ± 6.15; P < .001) with segmental lateral (P < .001) strain values. There were not any significant changes between 1- and 3-month follow-ups of all the values (P > .05). But it could be seen that values increased in 1- and 5-year follow-ups compared with the baseline of 1- and 3-month follow-ups (P < .05). The global and segmental strain of the right ventricle decreased more than that of the left ventricle in all HTx groups, and the strain values were decreased in the HTx groups compared with the CG, with the global decreased change rates being 11%, 10%, 6%, and 8%, respectively.

CONCLUSIONS

The strain values decreased after HTx and almost remained stable in the long-time follow-ups. Compared with the CG in both ventricles, they were with preserved or reduced functions. In addition, the deformation values of the right ventricle decreased more than those of the left.

Serial Changes in Right Ventricular Systolic Function Among Rejection-Free Children and Young Adults After Heart Transplantation

BACKGROUND

Evolution of right ventricular (RV) systolic function after pediatric heart transplantation (HT) has not been well described.

METHODS

We analyzed echocardiograms performed over the first year after HT among children and young adults who remained rejection-free. Ninety-six patients (median age 7.1 [0.1-24.4] years at HT) were included: 22 infants (≤1 year) and 74 noninfants (>1 year). Two-dimensional tricuspid annular plane systolic excursion (TAPSE), tissue Doppler-derived tricuspid annular systolic velocity (S'), fractional area change (FAC), myocardial performance index (MPI), and two-dimensional speckle-tracking-derived RV global longitudinal (GLS) and free wall strain (FWS) were assessed.

RESULTS

All measures of RV function were impaired immediately after HT and significantly improved over the first year: TAPSE z-score (-8.15 ± 1.88 to -3.94 ± 1.65, P < .0001), S' z-score (-4.30 ± 1.36 to -2.28 ± 1.33, P < .0001), FAC (24.37% ± 7.71% to 42.02% ± 7.09%, P < .0001), MPI (0.96 ± 0.47 to 0.41 ± 0.22, P < .0001), GLS (-10.37% ± 3.86% to -21.05% ± 3.41%, P < .0001), and FWS (-11.2% ± 4.08% to -23.66% ± 4.13%, P < .0001). By 1 year post-HT, TAPSE, S', GLS, and FWS, remained abnormal, whereas FAC and MPI nearly normalized. Patients transplanted during infancy demonstrated better recovery of RV systolic function.

CONCLUSIONS

Although RV systolic function improved over the first year after HT in children and young adults without rejection, measures that assess longitudinal contractility remained abnormal at 1 year post-HT. These findings contribute to our understanding of RV myocardial contractility after HT in children and young adults and improve our ability to assess function quantitatively in this population.

Echocardiographic Assessment of Right Ventricular Function in Clinically Well Pediatric Heart Transplantation Patients and Comparison With Normal Control Subjects

BACKGROUND

Echocardiographic follow-up after pediatric heart transplantation is important because of the lifelong risk for rejection and resultant ventricular dysfunction. Although adult studies have shown that echocardiographic measures of right ventricular function are changed after transplantation, similar results have not been reported in the pediatric population.

METHODS

A single-center retrospective study of echocardiograms obtained among pediatric heart transplant recipients was conducted. All echocardiograms were selected remote from transplantation, rejection, or graft vasculopathy. These criteria identified 127 patients. Right ventricular systolic function was measured using tricuspid annular plane systolic excursion, fractional area change (FAC), and peak systolic tricuspid annular tissue velocity (S'). Results were compared with those in 380 healthy age-matched echocardiographic control subjects.

RESULTS

Tricuspid annular plane systolic excursion values in pediatric heart transplant recipients were significantly lower than in control subjects at all ages (P < .0001), with a mean Z score of -3.38. FAC and S' did not vary by age in control patients >6 months of age. FAC values in transplantation patients were significantly decreased compared with those in control subjects (P < .0001), but 83% of transplantation patients had FAC values within the control-derived normal range. S' values were also significantly lower in transplantation patients than control subjects (P < .0001).

CONCLUSIONS

Heart transplantation patients have significantly decreased quantitative metrics of right ventricular function relative to healthy control subjects; longitudinal shortening (tricuspid annular plane systolic excursion and S') is particularly affected. FAC is relatively preserved and may be a better metric in this population. These results establish nomograms of RV function in pediatric heart transplantation patients and in normal pediatric control subjects, which may allow quantification of changes in this vulnerable population.

Early assessment of right ventricular systolic function after pediatric heart transplant

RV systolic function is important early after HT; however, it has not been critically assessed in children using quantitative measures. The aim of this study was to describe the most validated and commonly used quantitative echocardiographic measures of RV systolic function early after pediatric HT and to assess associations with qualitative function evaluation and clinical factors. RV systolic function was quantified on the first post-HT echocardiogram >24 hours after cardiopulmonary bypass using two-dimensional TAPSE, Tricuspid annular S', FAC, and MPI. In 145 patients (median age 7.6 years), quantitative RV systolic function was markedly abnormal: mean TAPSE z-score -8.43 ± 1.89; S' z-score -4.36 ± 1.22; FAC 24.4 ± 8.34%; and MPI 0.86 ± 0.51. Few patients had normal quantitative function: TAPSE (0%), S' (1.2%), FAC (9.4%), and MPI (28.4%). In contrast, 48.3% were observed as normal by qualitative assessment. Most clinical factors, including diagnosis, pulmonary vascular resistance, posttransplant hemodynamics, inotropic support, and rejection, were not associated with RV function. In this large pediatric HT population, TAPSE, S', FAC, and MPI were strikingly abnormal early post-HT despite reassuring qualitative assessment and no significant association with clinical factors. This suggests that the accepted normal values of these quantitative measures may not apply in the early post-HT period to accurately grade RV systolic function, and there may be utility in adapting a concept of normal reference values after pediatric HT.

Evaluation of the Graft Mechanical Function Using Speckle-Tracking Echocardiography During the First Year After Orthotropic Heart Transplantation

Background

Recent advances in ultrasound strain imaging facilitate more precise monitoring of subtle myocardial changes and thus may allow for more appropriate assessment of myocardium after orthotopic heart transplantation (OHT). This study aimed to explore longitudinal left ventricular (LV) and right ventricular (RV) function by speckle-tracking echocardiography (STE) during a 12-month follow-up period in relation to acute cellular rejection (ACR) degree ≥2R and the response to intense immunosuppressive therapy with intravenous steroids.

Material/Methods

Forty-five adult heart transplant recipients were prospectively assessed at a single center from January 2016 until June 2017. Echocardiography was performed serially at baseline and together with routine biopsies at 2 weeks and 1, 2, 3, 6, 9, and 12 months after OHT. Changes in graft function were evaluated using STE before and during ACR and in the resolving period of ACR.

Results

A total of 220 pairs of biopsy specimens and strain recordings were analyzed. Moderate ACR was seen in 30 biopsies (13.6%). In the serial assessment, longitudinal strain parameters of the LV (global and 4-, 2-, 3-chamber longitudinal strain) and RV (global and free wall longitudinal strain) were decreased at baseline and improved significantly (P<0.001) within 12 months after OHT. The degree of improvement was not influenced by ACR. There were no significant differences in circumferential, radial, or longitudinal strain rate, or mechanical dyssynchrony. Reduced LV and RV longitudinal strain was related to ACR degree 2R and increased significantly (P<0.0005) during 3 days of intravenous methylprednisolone therapy.

Conclusions

Using the STE technique, we have documented an acute improvement in mechanical myocardial function following ACR steroid therapy and a progressive recovery of LV and RV longitudinal function during the first year after OHT.

Dominance of free wall radial motion in global right ventricular function of heart transplant recipients

Assessment of right ventricular (RV) function using conventional echocardiography might be inadequate as the radial motion of the RV free wall is often neglected. Our aim was to quantify the longitudinal and the radial components of RV function using three-dimensional (3D) echocardiography in heart transplant (HTX) recipients. Fifty-one HTX patients in stable cardiovascular condition without history of relevant rejection episode or chronic allograft vasculopathy and 30 healthy volunteers were enrolled. RV end-diastolic (EDV) volume and total ejection fraction (TEF) were measured by 3D echocardiography. Furthermore, we quantified longitudinal (LEF) and radial ejection fraction (REF) by decomposing the motion of the RV using the ReVISION method. RV EDV did not differ between groups (HTX vs control; 96 ± 27 vs 97 ± 2 mL). In HTX patients, TEF was lower, however, tricuspid annular plane systolic excursion (TAPSE) decreased to a greater extent (TEF: 47 ± 7 vs 54 ± 4% [-13%], TAPSE: 11 ± 5 vs 21 ± 4 mm [-48%], P < .0001). In HTX patients, REF/TEF ratio was significantly higher compared to LEF/TEF (REF/TEF vs LEF/TEF: 0.58 ± 0.10 vs 0.27 ± 0.08, P < .0001), while in controls the REF/TEF and LEF/TEF ratio was similar (0.45 ± 0.07 vs 0.47 ± 0.07). Current results confirm the superiority of radial motion in determining RV function in HTX patients. Parameters incorporating the radial motion are recommended to assess RV function in HTX recipients.

Three-Dimensional Right Ventricular Strain Versus Volume Quantification in Heart Transplant Recipients in Relation to Pulmonary Artery Pressure

OBJECTIVES

Residual pulmonary hypertension challenges the right ventricular function and worsens the prognosis in heart transplant recipients. The complex geometry of the right ventricle complicates estimation of its function with conventional transthoracic echocardiography. We evaluated right ventricular function in heart transplant recipients with the use of 3-dimensional echocardiography in relation to systolic pulmonary artery pressure.

MATERIALS AND METHODS

We performed 32 studies in 26 heart transplant patients, with 6 patients having 2 studies at different time points with different pressures and thus included. Right atrial volume, tricuspid annular plane systolic excursion, peak systolic annular velocity, fractional area change, and 2-dimensional speckle tracking longitudinal strain were obtained by 2-dimensional and tissue Doppler imaging. Three-dimensional right ventricular volumes, ejection fraction, and 3-dimensional right ventricular strain were obtained from the 3-dimensional data set by echocardiographers. Systolic pulmonary artery pressure was obtained during right heart catheterization.

RESULTS

Overall mean systolic pulmonary artery pressure was 26 ± 7 mm Hg (range, 14-44 mmHg). Three-dimensional end-diastolic (r = 0.75; P < .001) and end-systolic volumes (r = 0.55; P = .001)correlated well with systolic pulmonary artery pressure. Right ventricular ejection fraction and right atrium volume also significantly correlated with systolic pulmonary artery pressure (r = 0.49 and P = .01 for both). However, right ventricular 2- and 3-dimensional strain, tricuspid annular plane systolic excursion, and tricuspid annular velocity did not.

CONCLUSIONS

The effects of pulmonary hemodynamic burden on right ventricular function are better estimated by a 3-dimensional volume evaluation than with 3-dimensional longitudinal strain and other 2-dimensional and tissue Doppler measurements. These results suggest that the peculiar anatomy of the right ventricle necessitates 3-dimensional volume quantification in heart transplant recipients in relation to residual pulmonary hypertension.

Right Ventricular Dysfunction as an Echocardiographic Measure of Acute Rejection Following Heart Transplantation in Children

Noninvasive biomarkers of acute allograft rejection (AAR) following orthotopic heart transplantation (OHT) are needed. The aim of this study was to investigate the accuracy of echocardiographic (ECHO) right ventricular (RV) global functional and resistance indices in the detection of AAR. This retrospective chart review included children with biopsy-proven AAR (grade ≥ 2R cellular or CD4 + antibody-mediated rejection) following OHT and an ECHO within 12 h of the biopsy. ECHO measures: (a) ratio of systolic to diastolic duration (S/D), (b) RV myocardial performance index (MPI) and (c) tricuspid regurgitant gradient to RV outflow tract velocity time integral ratio (TRG/VTI), were derived at baseline, during AAR and at two follow-ups. Sixteen patients [56% male, mean (SD) age at OHT 3.5 (4.3) years] had 16 AAR episodes. S/D (1.15 vs. 1.60, p < 0.01), RV MPI (0.19 vs. 0.39, p < 0.01) and TRG/VTI (1.05 vs. 1.7, p = 0.01) deteriorated during AAR and, except for diastolic duration, improved significantly at first follow-up. The negative predictive values for S/D, RV MPI and TRG/VTI at cutoffs of 1.3, 0.31 and 1.3 were 97, 97 and 87%, respectively. RV S/D, MPI and TRG/VTI deteriorated during AAR. Their excellent negative predictive values suggest that their incorporation in surveillance may obviate the need for routine biopsies.

Serial changes in longitudinal graft function and implications of acute cellular graft rejections during the first year after heart transplantation

AIMS

The aim of this prospective study was to use left ventricular global longitudinal strain (LV-GLS) as a non-invasive tool for the monitoring of graft function in relation to acute cellular rejection (ACR) during the first year after heart transplantation (HTX).

METHODS AND RESULTS

The study population consisted of 36 patients undergoing HTX from November 2010 until October 2013. Patients were followed by comprehensive echocardiography and biopsies at 2 weeks and 1, 3, 6, and 12 months after HTX. ACRs were classified based on the ISHLT classification (0R-3R). Patients were divided into two groups according to the presence of one or more episodes of biopsy proven ≥grade 2R ACR during follow-up. We found that LV-GLS and tricuspid annular plane systolic excursion (TAPSE) were significantly related to ACR burden in a linear regression model. The absolute difference in LV-GLS between patients in the ACR group (-14.4%) and patients in the ACR-free group (-16.8%) was -2.4% (P < 0.01) 12 months after HTX. In the ACR group, patients' LV-GLS did not improve between 1 and 12 months, whereas an improvement of -2.9% was seen in the ACR-free group in this period (P < 0.01). The two groups appeared not to differ in terms of diastolic Doppler parameters or LV ejection fraction, but TAPSE was 15.3 ± 2.8 mm in the ACR-free group vs. 13.2 ± 2.1 mm ACR group, P < 0.05, 12 months after HTX.

CONCLUSION

Gradual improvement of longitudinal LV and RV function was seen within the first year after HTX, but the degree of recovery was strongly influenced by ACR episodes.

Altered Right Ventricular Contractile Pattern after Cardiac Surgery: Monitoring of Septal Function Is Essential

Assessment of right ventricular (RV) function is important in the management of various forms of cardiovascular disease. Accurately assessing RV volume and systolic function is a challenge in day‐to‐day clinical practice due to its complex geometry. Tricuspid annular plane systolic excursion (TAPSE) and systolic excursion velocity (S′) have been reviewed to further assess their suitability and objectivity in evaluating RV function. Multiple studies have validated their diagnostic and prognostic values in numerous pathologic conditions. Diminished longitudinal contraction after cardiothoracic surgery is a well‐known phenomenon, but it is not well validated. Despite significant reduction in RV performance along the long‐axis assessed by TAPSE and S′ after cardiac surgery, RV ejection fractions did not change as well as the left ventricular parameters and exercise capacity. RV contractile patterns were markedly altered with decreased longitudinal shortening and increased transverse shortening, which are likely resulted from the septal damage during cardiac surgery. The septum is essential for RV performance due to its oblique fiber orientation. This allows ventricular twisting, which is a vital mechanism against increased pulmonary vascular resistance. The septum function along with TAPSE and S′ should be adequately assessed during cardiac surgery, and evidence of septal dysfunction should lead to reevaluation of myocardial protection methods.